But then, after a sigh, because, after all, he's agreed to talk about his life and career in a wide-ranging interview with CNBC, Belichick offers: "I think I know a little about coaching. I think I know a little about leadership."

You think?

Love the Patriots or hate them, Belichick's 209-78 record for New England says it all. Football teams do not lead themselves, and they certainly do not lead themselves to five Super Bowl victories.

So, according to Belichick, what exactly is the "little" he knows about leadership? His answer, it turns out, could fill a book, but here are the top five principles that emerged over nearly two hours of conversation.

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1. Leadership means building a team that's exhaustively prepared, but able to adjust in an instant

"The only sign we have in the locker room is from 'The Art of War.' 'Every battle is won before it is fought,'" says Belichick, who started breaking down films of opposing teams when he was 7 years old and hanging out with his dad, Steve, an assistant coach at Annapolis.

"You [have to] know what the opponents can do, what their strengths and weaknesses are ... [and] what to do in every situation," he says.

That ability — to adapt on a dime — is why Belichick says he spends so much time building teamwork, from having the team train with Navy SEALs, to organizing trivia nights, where, incidentally, all social media is banned.

"Nobody is against [social media] more than I am. I can't stand it," Belichick says. "I think it's important for us, as a team, to know each other. Know our teammates and our coaches. To interact with them is more important than to be 'liked' by whoever on Chatrun." (In the same conversation, he also derided "InstaFace" in all seriousness.)

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2. Leadership means having the discipline to deploy your "dependables"

You know your star performers? The ones who can dazzle and amaze, except when they don't? They're definitely appealing, Belichick admits.

But over the years, he's learned they're not his type. He'd rather stick with his tried-and-true people — call them his "dependables."

"There have been times when I've put too much responsibility on people. ... They might have been the most talented, or the people you hoped would do the right or best thing, and they didn't come through," Belichick says.

Big mistake.

When it comes to getting things done, especially critical things, forget the high flyers: "You have to go with the person who you have the most confidence in, the most consistent," Belichick says. "And if it doesn't work, it doesn't work, but I'm going down with that person."

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3. Leadership means being the boss

Belichick says this principle first came to him when he was just 23, addressing the Colts as a special teams coach. Two players, one of them a talented starter, spent the beginning of the meeting giggling and chatting. Inside, Belichick recalls, he was seething: "I'm not afraid of these guys. It's either [them] or me. We can't run a team like this."

Finally, he let loose. "Look, either you shut up or you get out of here. That's it."

It worked.

And it was an aha moment that has guided him since. "I don't care if they're a star player," he says. "I don't care who they are. You have to set the tone."

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4. Leadership means caring about everything going on in the lives of your people

Maybe the previous rule would make you think otherwise, but Belichick strongly believes you must see your team not just as players, per se, but as people who have full, three-dimensional, and often messy lives.

"There are a lot of things that affect what happens on the field that occur off the field," he says. Players "have wives and girlfriends. And they have babies. And they have personal situations. They have parents that are sick. All of it runs in together."

Work and life, in other words, are inseparable, and it's incumbent on leaders to help their people sort through it. "The more you and the organization can help take care of personal situations," he says, "the smoother the ship runs on the football end."

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5. Leadership means never resting on your laurels

Ask Belichick if he's still celebrating the stunning come-from-behind Super Bowl victory in February and you get another "You're killing me here" look.

"We're onto 2017. No one cares about 2016 anymore," he says. "You can't look back. We don't talk about last year. We don't talk about next week. We talk about today, and we talk about the next game. That's all we can really control."